Spline hobbing apparatus



. N v- 3, 193 H. w. JACOBSON ET AL 1,830,659

SPLINE HOBBING APPARATUS Filed June 1, 1927 3 Sheets-Sheet 1 N awuemtou77 k 5 W 2 .WW M W Nov. 3, 1931. H. w. JACOBSON ET AL 1,830,659

SPLINE HOBBING APPARATUS Filed June 1, 1927 s Sheets-Sheet 2 avwewcomNov. 3, 1931. H. w. JACOBSON ET AL SPLINE HOBBING APPARATUS Filed June1, 1927 :5 Sheets-Sheet 3 Patented Nov. 3, 1931 nneo w. JACOBSON, orARLINGTON, Aim

CLAIR, NEW JERSEY, ASSIGNORS TO GOULD & EBERHARDT, O1 JERSEY, ACORIE'ORATION OF NEW JERSEY PATENT oFFi'cE naoun A. DEMEILLERS, or UPPERMoNT srLiNr: HOBBINGV APPARATUS Application filed June 1,

In a co-pending sole application filed May :6, 1927, Serial No. 189,35there is set forth a methodforgenerating multi-splined shafts V which iswell adapted to be performed with the aidance of various convenientdevices. The hereindescribed joint invention represents our compositeeffort to render available instrumentalities especially suitable for usein carrying out an analogous method of op- .eration.

Our aim-has been sotocontrive the fixtures that they will beco-operatively compatible with the successive steps and manipulationsconstituting a method of generating multi- .1 splines, and so that theymay admit of being handled with much facility, and so that they may alsocontribute to the ready attainment of a high order of precision. V V

Multi-splined shafts have, as all know, gone widely into usage and everyefiort has been and is being, bent by the various makers thereof toimprove the methods and means for producing them. Our researches haveindicated, of all the ways in which they may be made, a generation bythe action of a hob best satisfies the requirements of production, costand quality.

We have, accordingly, sought to provide a conventional gear hobbingmachine (which otherwise cannot well do this work) with equipmentpeculiarly adapting it for the commercial production of elongated highgrade multi-splined shafts. To spline by hobbing a short length orashort shaft, is one thing; but to hob a long shaft is quite anotherthing; that is to sayby utilizinga conventional machine in which thetraverse of the hob carrier is comparatively short. Consequently, suchan elongated operation must be performed in successive sections orsteps.

' This means that the shaft must be released,

lpair or prohibit the free-sliding of the shift- "el'ement which'isintended to be mounted on 1927. Serial No. 195,650.

NEWARK, .NEW

that shaft in close interfitting relation with if its spline grooves.

other objectives, also concerned. It proposes the use of a clutch(preferably a'collet) for grasping the shaft successively atintermediate stations for driving it. With that collet, it combinedmeansadapted to-be clamped to eing'age the shaft positively preparatoryto each disengagement of it by the collet; all for the purpose ofenabling the relation between the hob and the spline groovespreviouslycut thereby. to be precisely established so as to be exactlyensured at the time the collect is again tightened on the shaft whichhas been freed and shifted longitudinally preparatory to hobbing thenext section.- This is in the nature of a specialized precision indexingmeans. This indexing means is caused to grip the shaft near the collet.After the shaft has'been released-by the collet, the shaft and freecollet being then relatively shifted, this means (which will now belocateddistant from the collet) will nevertheless enablethe collet to'beagainclosed on the shaft inexactly the identical angular relationthereto that existed previous to its release. This ensures the utmostuniformity from one end to the'other of the sectionallyforme'd'splinegrooves; to wit, by preserving the relationship between the hob and "theshaft throughout the aggregate cycles of operation. j

' Other objects and advantages. will be'in part indicated in thefollowing description and in part rendered apparent therefrom inconnection with the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlyingfeatures hereof that they may embody the samein the various wayscontemplated by this invention. drawings depicting a preferredtypical'construction have been annexed as a part of this disclosure and,in such .drawings, like characters 'of reference denote correspondingith that problem this invention is, among,

parts throughout all the views, of which Figure 1 diagrammaticallydepicts a hobbing machine embodying this invention; the parts beingarranged preparatory to starting the 'splinin-g of an elongated shaftyFig.

detail representing in verticalsection a' collet suitable for graspingand rotating the shaft. Fig. 4 is a section through line 4:4 of Fig.

3. Fig. 5 is a plan of a follower suitable for maintaining the shaftagainstdeflection under the action of the hob. Fig. 6 is afragmentaryside elevation showing an indexing fixture for establishing andreproducing the identical relation between the hob and the splinegrooves, this fixture being used especially during the so-calledfinishing operations. F1g. 7 is a plan of the arrangement shown by *ig.6. 1

It will be noted that'the drawings depict a hobber of the vertical type.The motive of that is two-fold; first, to avoid the deflections andstrains tending-to cause deflection existing in all locally-supportedhorizontal shaft, and second, to economize valuable factory floor spaceotherwise pre-empted by any elongated horizontal shaft.

Referring to-Figs. 1 and 2, A denotes the bed of a hobbing machine whichsupports a rotatable table B carrying a suitable shaftgrippin chuckpreferably in the nature of a collet such as has been illustrated byFigs. 3 and 4. The collet C, the turn table B, and the bed A are soformed as to provide for the reception of an elongated vertical shaftand, to that end, the floor or ground on which thebed A rests maybeprovided with a vertical hole or well sufficiently deep to receive aconsiderable portion of the full length of the longest shaft that willneed to be splined.

To prevent side sway of the upper portions of the shaft (indicated byD)which would otherwise be free, it is proposed to provide means in thenature of'a pilot. This pilot is carried by a standard E and itsdistance from the collet C may be regulated by means of a slide blockFwhich may be adjustably secured to the guideway e presented by thestandard E which normally'rests securely on the bed A. To accommodatedifferent sizes of shafts, and different journals at the ends of saidshaft, the pilot means is preferably made interchangeable. That is tosay, Gr indicates a pilot element proper which is detachably secured tothe block F by means of a bolt 7 and this pilot G is apertured to carrya pilot bushing 9 adapted snugly to interfit with the journal end (Z ofthe shaft D thereby bracing the extremity of the shaft preparatory tocutting splines therein.

It may here be explained that, after cutting the first section of theshaft, it is desirable to use a pilot element such as G for bracing theshaft at the startof the down stroke of the hob and'the pilotelement, inthat case,'will be adapted to journal the body portion of the shaftclosely by virtue of p ro art to represent elements conventionally usedin a hobbing machine; to wit, the usual transmission system forsimultaneously rotating the turntable and the hob; for feeding thehob-headdownwardly to the end of its available stroke; and returning tothe upper end of the stroke: These details, for the sake of clearness,are therefore omitted from the drawings as not beingnecessary to acomprehension of the features of this 'inven tion.

The collet C comprises a tubular body portion indicated by lon Fig.3having a base 2 adapting it, by means of bolts such as 3, to be securedconcentrically to the axis of the turn table B. This member operates asa means for receiving the collet element proper which is indicated by Gand comprises a tubular shank 4 having a number of longitudinal splits 5to form a series of resilient fingers 6'. Near their outer ends, thesefingers provide inclines 7 which co-operate with a conical seat 8 in themember 1 so that, when the collet proper G is forced downwardly, thefingers will be pressed to grip the shaft passing through the bore ofthe collet proper. This closing is accomplished-by means of a closer Cwhich is screw threaded at 9 to the body 1 and has an overhanging rim 1Ooperative upon a non-rotatable thrust ring 11, and provided withsuitable side slots 12 to admit of being turnedby a spanner wrench. Theutility of the thrust ring 11 is to prevent any rotation of the colletcloser C r from being communicated to the collet proper C. Thisenablesgreat precision in indexing to be attained inasmuch as there isno tendency towards angular displacement upon the reclamping of theshaft.

Upon clamping the shaft in the collet with the parts in the positionindicated by Fig. 1, the cutting of the splines may be begun; thefollower indicated by Fig. .5 being assumed to be opened and set back soas to clear the pilot element G. As soon as the follower. M

. (which is held by a set screw in the bracket N affixed to thehead I)has been brought into 7 horizontal coincidence with the body portion ofthe shaft D, it is slipped towards the shaft and turned until its mainhalf section snugly 1 ings 15; and 16 to insure a snug yet free turningifit. o 7 I he cutting operation is then proceeded with dnsringtthe downfeed of the hob-head I; and the shaft is roughed out by a, cyclicoperation through the adding of this instrumentality in the mannerdetailed in the copending application of Hugo W. Jacobson hereinreferred to.

It is-during the finish-cuttingof the splined shafts that the indexinginstrumentality assumes'itsgreatest importance. Fig.v 2 represents apart of the finishing operation. The shaft is inserted in the collet. Toalign its ronghed out grooves with the finishing hob so that the lattermay take finished cuts of each side wall of each groove, a preliminaryalignment is obtained by means of a setting finger P mounted in astandard Q, which is adapted torest on and interfit with one of theradial T-slots conventionally provided by the turn table B. This is donewhen the shaft is in the lowermost position and before the hob hasentered any of the grooves. The. hob-head is then fed'downwardlysufficiently to enable the hob to take a short finishcut and to causethe follower to pass the pilot (as. explained in connection with Fig. 1)and the first section of the finished cut is then pursued with thefollower riding behind the hob and journaledagamst side sway. 7

At the end of the first down feed, the angular relation of the hob tothe shaft is precisely established. This is done by the fixture shown byFigs. 6 and 7. This indexing fixture (indicated generally by R comprisesa ring 17 having a hole fluted in general correspondence with thesplines of the shaft as indicated by 18. A thumb screw 19 extends in atangential direction to one of the flutes, the object being to enablethe thumb screw to press against the side wall of one of the splines ofthe shaft and urge it securely against a corresponding flute 20 of thering 17. This establishes definite angular relation between the indexingdevice R and the splines of the shaft. This index device is providedwith an elongated finger 21 having at its extremity an index line 22which, by means of an element S adjustable on the head I, may be causedto coincide with a corresponding line 24. The screws 23, being newtightened, will fix this relationship. The index device may now beremoved. The hob head may be elevated and the shaft unclamped. The shaftmay then be elevated; the index device restored and clamped to the shaftand turned if necessary to bring the lines 22 and 24 into coincidence.The collet is now tightened with perfect assurance that the relationshipbetween the hob and the spline grooves has not suffered alteration. Thefinish-splining of the next section may now be carried out; and so oncyclically until a sufficient length of the shaft has been splined.

lVithout further analysis, the foregoing will so fully reveal the gistof this invention that others can, by applying current knowledge,readily adapt'it for various utilizations by reta ning one or more ofthe features that, from the standpoint of the prior Having thus revealedthis invention, we

claim as new and desire to secure the following combinations andelements, or equivalents thereof, by Letters Patent of United States .1.A multi-spline hobber combining a retatable collet; a shiftablehob-support; a rotatable hob adapted to generate splines in a shaftcarried by said collet; and an indexing member adapted positively toengage said shaft to establish definitely therelati'on of its splineswith said hob and to enable said collet to be unclamped and then re.-clamped with said relation exactly reproduced. Y

2. A multi-spline hobber combining a 1'0- tatable collet; a. shiftablehob-support; a r0 tatable hob adapted to generate splines in a shaftcarried by said collet; and an indexing member adapted positively tointerfit with splines cut in said shaft to establish definitely therelation of. its splines with said hoband to enable said collet to beunclamped and then reclamped to expose an additional length of the shafttothe action of the hob with said relation exactly maintained.

.3. A multi-spline hobber combining a retatable collet; a shiftablehob-support; a rotatable hob adapted to generate splines in a shaftcarried by said collet; and a detachable indexing member adaptedpositively to be affixed to said shaft to'establish definitely therelation of its splines with said hob; said member being adapted to bethen re moved to enable said collet to be unclamped and said shaft andhob shifted; and said member being adapted again to be aifixed to saidshaft to enable it to be reclamped with i said relation exactlyreproduced.

' l. A multi-spline hobber combining a rograsped by said collet.

6. A multi-spline" hobber combining an erect collet adapted to rotate ashaft and to hold it against axial movement; an upright stanchion; ahob-head feedable vertically therealong; a hob journaled on said head,said hob and collet being adapted to be simultaneously rotated; astandard; a displaceable pilot supported by said standard for co-axiallyjournaling the free end of the shaft, grasped by the collet, said pilotforming a bearing for said shaft at the side of said hob remote fromsaid collet during the 7 initial portion of the hobbing operation; and ashaft-embracing follower carried by said feedable hob-head and adapted,after the initial portion of the hobbing operation has been com leted,to be placed around and form a mova le bearing for the shaft at the sideof the hob remote from the collet during the remainder of the hobbingoperation.

7. A multi-spline hobber combining an erect collet adapted to rotate ashaft and to hold it against axial movement; an upright stanchion; ahob-head feedable vertically therealong; a hob journaled on said head,

' said hob and collet being adapted to be simultaneously rotated; astandard; a displaceable pilot supported by said standard for co-axiallyjournaling a shaft grasped by the collet; and a follower carried by saidfeedable hob-head and comprisinga main half section, a cap-sectionhinged thereto, semi-circular bushings carried by said sections, andmeans to hold said sections together with said bushings engaging saidshaft.

8. A multi-spline hobber combining a rotatable work-holder adapted torotate a Work-piece and hold it against axial movement; a support; ahob-head feedable on said support parallel to the axis of saidwork-piece; a hob journaled on said head, said hob and collet beingadapted to be rotated simultaneously; and a journal for said work-piecesupported by and movable with said hob-head during a feeding movement ofsaid hob-head.

9. In a spline hobbing machine adapted to perform roughing and finishingcuts, a rotatable turn-table; a work-holder carried thereby and adaptedto rotate a work-piece and hold it against axial movement; a stanchion;a hob-head feeda-ble on said stanchion parallel to the axis of saidwork-piece'and adapted selectively to carry roughingiand finishing hobs,said hobs and Work-holder being adapted to" be rotated simultaneously;and means carried by said turn-table to en'- gage one ofthe rough-cutsplinesthereby to position said splines relative to a finishing hob fora finishing operation.

10. In a multi-spline hobbing machine adapted selectively to performroughingand finishing cuts; a rotatable. work-holder adapted to rotate awork-piece andihold it against axial'moveme-nt; a stanchion; a hobheadfeedable onsaid stanchion parallel to the axis of said work-piece andadapted to carry roughing and finishing hobs, said hobs and work-holderbeing adapted to be simultaneously rotated; a follower carried'by' saidhob-head" and affording a movable bearing for said Work-piece adjacentthe hob; and a setting device-adapted to engage one of the rough-cutsplines thereby to position said splines relative to afinishing hob forafinishing operation. 'I '1 In Witness whereof, we have hereunto subscribed our names. V

HUGOv W. JACOBSON. RAOUL' A. DEMEILLERS.

